<!doctype html>
<html lang="en" style="height: 100%">

<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">

  <title>Markdown Here Test</title>
  <meta name="description" content="">
  <meta name="author" content="">

  <meta name="viewport" content="width=device-width, initial-scale=1.0">
</head>

<body style="height: 100%">
  <iframe style="height: 100%; width: 100%;">
  </iframe>

  <script>
    document.addEventListener('DOMContentLoaded', function() {
      var body = document.querySelector('iframe').contentDocument.body;
      body.setAttribute('contenteditable', true);
      body.focus();
    });
  </script>
</body>

</html>
